import { setTimeout } from "timers";

let pro1 =  new Promise((resolve,reject) => {
    resolve(1);
    return;
});

pro1.then(function(i:number){
    return new Promise(function(resolve,reject){
        setTimeout(function(){
            resolve(++i);
        },2000);
    });
}).then(function(i:number){
    console.log(i);
});


